Direct-View Bistable Storage Tubes (DVBST) was an acronym used by Tektronix

Tektronix

Tektronix, Inc. is an American company best known for its test and measurement equipment such as oscilloscopes, logic analyzers, and video and mobile test protocol equipment. In November 2007, Tektronix became a subsidiary of Danaher Corporation....

 to describe their line of storage tubes

Storage tube

Mostly obsolete, a storage tube is a special monochromatic CRT whose screen has a kind of 'memory' : when a portion of the screen is illuminated by the CRT's electron gun, it stays lit until a screen erase command is given...

. These were cathode ray tube

Cathode ray tube

The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...

s (CRT) that stored information written to them using an analog technique inherent in the CRT and based upon the secondary emission

Secondary emission

Secondary emission in physics is a phenomenon where primary incident particles of sufficient energy, when hitting a surface or passing through some material, induce the emission of secondary particles. The primary particles are often charged particles like electrons or ions. If the secondary...

 of electrons from the phosphor screen itself. The resulting image was visible in the continuously glowing patterns on the face of the CRT.

DVBST technology was anticipated by Andrew Haeff of the (United States) US Naval Research Laboratory

United States Naval Research Laboratory

The United States Naval Research Laboratory is the corporate research laboratory for the United States Navy and the United States Marine Corps and conducts a program of scientific research and development. NRL opened in 1923 at the instigation of Thomas Edison...

, and by Williams and Kilburn in the late 1940s. Tek's (Tektronix) Robert H. Anderson refined Haeff's concepts in the late 1950s to produce a reliable and simple DVST.

Tektronix-made DVBSTs were used for analog oscilloscopes (first in the 564 oscilloscope, then the type 601 monitor (1968), the 611 monitor, the 7613 plug-in mainframe oscilloscope, all from Tektronix) and for computer terminals such as the archetypal Tek 4010 and its several successors including the Tektronix 4014

Tektronix 4014

The Tektronix 4000 series was a family of text and graphics computer terminals based on the company's storage tube technology. No additional electronics were needed to maintain the display, so the 4000 series were less expensive than earlier graphics terminals and became widely used in the CAD...

. Portions of the screen are individually written-to by a conventional electron beam gun, and "flooded" by a wide, low velocity electron gun. Erasure required erasing the entire screen in a bright flash of green light, leading to the nickname "the mean green flashin' machine".

Some DVBST implementations also allowed the "write-through" of a small amount of dynamically refreshed, non-stored data. This allowed the display of cursor

Cursor (computers)

In computing, a cursor is an indicator used to show the position on a computer monitor or other display device that will respond to input from a text input or pointing device. The flashing text cursor may be referred to as a caret in some cases...

s, graphic elements under construction, and the like on computer terminals.

Skiatron

Another version of a (non-Tekronix) DVBST was the "dark trace" CRT also known as the Skiatron. This CRT replaced the conventional light-emitting phosphor

Phosphor

A phosphor, most generally, is a substance that exhibits the phenomenon of luminescence. Somewhat confusingly, this includes both phosphorescent materials, which show a slow decay in brightness , and fluorescent materials, where the emission decay takes place over tens of nanoseconds...

layer on the face of the tube screen with a scotophor

Scotophor

A scotophor is a material showing reversible darkening and bleaching when subjected to certain types of radiation. The name means dark bearer, in contrast to phosphor, which means light bearer. Scotophors show tenebrescence and darken when subjected to an intense radiation such as sunlight...

such as potassium chloride

Potassium chloride

The chemical compound potassium chloride is a metal halide salt composed of potassium and chlorine. In its pure state, it is odorless and has a white or colorless vitreous crystal appearance, with a crystal structure that cleaves easily in three directions. Potassium chloride crystals are...

 (KCl). KCl has the property that when a crystal is struck by an electron beam, that spot would change from translucent white to a dark magenta

Magenta

Magenta is a color evoked by light stronger in blue and red wavelengths than in yellowish-green wavelengths . In light experiments, magenta can be produced by removing the lime-green wavelengths from white light...

 color. By backlight

Backlight

A backlight is a form of illumination used in liquid crystal displays . As LCDs do not produce light themselves , they need illumination to produce a visible image...

ing such a CRT with a white or green circular fluorescent lamp

Fluorescent lamp

A fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp converts electrical power into useful...

, the resulting image would appear as black information against a green background or as magenta information against a white background. A benefit, aside from the semi-permanent storage of the displayed image, is that the brightness of the resultant display is only limited by the illumination source and optics.

The image would be retained until erased by flooding the scotophor with a high-intensity infrared light or by electro-thermal heating. Using conventional deflection and raster

Raster scan

A raster scan, or raster scanning, is the rectangular pattern of image capture and reconstruction in television. By analogy, the term is used for raster graphics, the pattern of image storage and transmission used in most computer bitmap image systems...

 formation circuity, a bi-level image could be created on the membrane and retained even when power was removed from the CRT. By using an array of dots, say 8 × 8, a larger pixel could be formed to represent 64 gray levels. One such device, the D38 Image Display, was made by DICOMED

DICOMED

Dicomed was founded in 1968 and in the early 1970s became a leading manufacturer of precision color film recorders such as the D47 and D48.-Use:...

 Corporation and a technical paper was presented at the 1972 Electro-Optical Conference in Geneva

Geneva

Geneva In the national languages of Switzerland the city is known as Genf , Ginevra and Genevra is the second-most-populous city in Switzerland and is the most populous city of Romandie, the French-speaking part of Switzerland...

, Switzerland

Switzerland

Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

.